With respect to the causes of variability, we are in all cases ver y ignorant; but we can see that in man as in the lower animals, they stand in some relation to the conditions to which each species has been exposed, during several generations. Domesticated animals var y more than those in a state of nature; and this is apparently due to the diversified and changing nature of the conditions to which they have been subjected. In this respect the different races of man resemble domesticated animals, and so do

In 1609, Galileo, then Professor of Mathematics at Padua, in the service of the Venetian Republic, heard from a correspondent at Paris of the invention of a telescope, and set to work to consider how such an instrument could be made. The result was his invention of the telescope known by his name, and identical in principle with the modern opera-glass. In a maritime and warlike State, the advantages to be expected from such an invention were immediately recognised, and Galileo was rewarded with a confirmati

The apple-tree is the common people's tree, moreover, because it is the child of ever y latitude and ever y longitude on this continent. It will grow in Canada and Maine. It will thrive in Florida and Mexico. It does well on the Atlantic slope; and on the Pacific the apple is portentous. Newton sat in an orchard, and an apple, plumping down on his head, started a train of thought which opened the heavens to us. Had it been in California, the size of the apples there would have saved him the trouble of much

But if, admitting this, we proceed to consider how the special aptitude of vespertina is constituted, or what it is that puts diurna at a disadvantage, we find ourselves quite unable to show the slightest connexion between the success of one or the failure of the other on the one hand, and the specific characteristics which distinguish the two forms on the other. The orthodox Selectionist would, as usual, appeal to ignorance. We ask what can vespertina gain by its white flowers, its more lanceolate leaves,

Sweet clover is an important forage crop in many regions. Although one of the oldest of known plants, not until ver y recently has it been considered seriously as a forage plant in this country. The principal causes for not utilizing this crop were its aggressiveness on uncultivated land in many localities, the tendency of the stems to become woody as they mature, and the refusal of stock to eat sweet clover before they had become accustomed to the bitter taste. Another reason was the fact that until recent

Many a mind misinterprets the thing seen, sometimes innocently, and again wantonly. The nature fakir is always on the alert to see wonderful phenomena in wild life, about which to write; and by preference he places the most strained and marvellous interpretation upon the animal act. Beware of the man who always sees marvellous things in animals, for he is a dangerous guide. There is one man who claims to have seen in his few days in the woods more wonders than all the older American naturalists and sportsme

What is the object of cultivating the soil? What is necessar y in order to cultivate with economy? Are plants created from nothing? The object of cultivating the soil is to raise from it a crop of plants. In order to cultivate with economy, we must raise the largest possible quantity with the least expense, and without permanent injur y to the soil. Before this can be done we must study the character of plants, and learn their exact composition. They are not created by a mysterious power, they are merel

Climbing plants may be divided into four classes. First, those which twine spirally round a support, and are not aided by any other movement. Secondly, those endowed with irritable organs, which when they touch any object clasp it; such organs consisting of modified leaves, branches, or flower-peduncles. But these two classes sometimes graduate to a certain extent into one another. Plants of the third class ascend merely by the aid of hooks; and those of the fourth by rootlets; but as in neither class do t

Fluids gravitate in proprio loco, the upper Parts continually pressing upon the lower: That this Pressure is not only propagated Downwards, but even Upwards, and Sideways, according to all possible Directions; That a lighter Fluid may gravitate upon a heavier, and an heavier upon a lighter; That a Fluid may sustain a Body heavi­er in Specie than it self, and even raise it up; That a Fluid may detain a Body lighter in Specie than it self, and even depress it. A gen-eral Experiment to prove, that a competent

Meteorology is the science of the atmosphere and its phenomena, including weather. Nowadays, when we speak of a meteor, we generall ean a shooting star; but formerly this term was applied (and it still often is in technical literature) to a great variety of phenomena and appearances in the atmosphere, including clouds, rain, snow, rainbows, and so forth. That is how the science of the atmosphere came to have its present name. Meteorology is not a branch of astronomy. These two sciences are as different from

A steam engine is a device by means of which heat is transfor­med into work. Work may be defined as the result produced by a force acting through space, and is common-ly measured in fo­ot-pounds; a foot-pound represents the work done in raising 1 pound 1 foot in height. The rate of doing work is called power. It has been found by exper-iment that there is a definite relati­on between heat and work, in the ratio of 1 thermal unit to 778 foot-pounds of work. The number 778 is commonly called the heat equiv-al

Biographical Sketch of Nikola TeslaBiographical Tesla While a large portion of the European family has beensurging westward during the last three or four hundredyears, settling the vast continents of America, another, buts maller, portion has been doing frontier work in the Old World, protecting the rear by beating back the unspeakable Turk and reclaiming gradually the fair lands that endure the curse of Mohammedan rule. For a long time the Slav people—who, after the battle of Kosovopjolje, in which the Tur

The Author offers the following book as a continua­continua­tion, in a more generally accessible form, of the Series tion, of Memoirs of Industrial Men introduced in his Lives of the Engineers. While preparing that work he fre­of fre­quently came across the tracks of celebrated inventors, quently mechanics, and iron-work-ers—the founders, in a great measure, of the modern indus-try of Britain—whose la­measure, la­bours seemed to him well worthy of being traced out bours and placed on record, and the more so

In this book the author has sketched swiftly the slow stages by which in each of these fields of activity success has beenby beenattained. He has collated from the immense mass of records ofattained. Of the activities of both submarines and aircraft enough interestingthe interesting data to show the degree of perfection and practicability to whichdata which both have been brought. And he has outlined so far as possibleboth possible from existing conditions the possibilities of future usefulness infrom in fi

I have been induced by various circumstances to collect in One Volume the Fourteen Series of Experimental Researches in Electricity, which have appeared in the Philosophical Transactions during the last seven years: the chief reason has been the desire to supply at a moderate price the whole of these papers, with an Index, to those who may desire to have them. The readers of the volume will, I hope, do me the justice to remember that it was not written as a whole, but in parts; the earlier portions rarely h

Several years ago, at the regular annual meeting of one of the major engineering societies, the president of the society, in the formal address with which he opened the meeting, gave expression to a thought so startling that the few laymen who were seated in the auditorium fairly gasped. What the president said in effect was that, since engineers had got the world into war, it was the duty of engineers to get the world out of war. As a thought, it probably reflected the secret opinion of every engineer pres

Geology is a science of such rapid growth that no apology is expected when from time to time a new textbookapology textbook is added to those already in the field. The presentis present work, however, is the outcome of the need of a text-book ofwork, of very simple outline, in which causes and their consequencesvery consequences should be knit together as closely as possible,—a needshould need long felt by the author in his teaching, and perhaps bylong by other teachers also. Th e author has ventured, there

And you, reader,—for without a reader there is no writer,—you are half of my work. Without you, I am only sounding brass; with the aid of your attention, I will speak marvels. Do you see this passing whirlwind called SOCIETY, from which burst forth, with startling brilliancy, lightnings, thunders, and voices? I wish to cause you to place your finger on the hidden springs which move it; but to that end you must reduce yourself at my command to a state of pure intelligence. The eyes of love and pleasure are p

For a work of such scope as wthis, the first word of the author should be an apology for what is doubtless the too ffambitious effort of a single writer. A quarter of a century in the high tide of the arts and sciences, an ardent interest in all things that make for scientific progress, and the aid and encouragement of many friends in and about the Patent ffThOffice, furnish the explanation. The work cannot claim the authority of a text-book, the fullness of a history, nor the exactness of a technical treat

There are certain events that must happen in a gasoline motor before the engine will run of its own accord. For instance, to obtain successive power impulses, the charge must first be admitted to the cylinder and compressed; it must then be ignited to form the explosion that creates the force at the flywheel; and the burned gases resulting from this explosion must be ejected in order to clear the cylinder for the new charge. To accomplish this series of events, some motors require four strokes, while other